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(CNN) -- Mali and Ghana are through to the semifinals of the Africa Cup of Nations after both achieved hard-fought quarterfinal victories on Sunday. Barcelona midfielder Seydou Keita scored the winning spot-kick for Mali as they defeated co-hosts Gabon 5-4 on penalties after the match finished 1-1 after 120 minutes in Libreville. Meanwhile, an extra time winner from Andre Ayew proved enough for World Cup quarterfinalists Ghana to edge past Tunisia 2-1 in the second match in Franceville. Mali will now face Ivory Coast in the last four, while a semifinal showdown with Zambia now awaits Ghana. Gabon looked on course to reach the last four for the first time in their history when Pierre-Emerick Aubameyang set up Eric Mouloungui for a 55th minute opener. And the scoreline remained that way until six minutes from time when Bordeaux striker Cheick Diabate turned and fired home an equalizer for Mali. With both sides scoring their first four penalties, Gabon's star player Aubameyang saw his spot-kick saved by Mali keeper Soumaila Diakite, leaving Keita to coolly slot home for Mali. Ghana continued their march towards a fifth Africa Cup of Nations title by seeing off a Tunisian side that ended the match with 10 men. Captain John Mensah opened the scoring for Ghana in the 10th minute, when he headed home a left-wing corner. Tunisia leveled three minutes before the break when Evian striker Sabeur Khalifa bravely headed in Zouhaier Dhaouadi's teasing cross from the right. But Ghana secured the victory after 101 minutes when Tunisia goalkeeper Aymen Mathlouthi dropped a harmless-looking cross for Ayew to roll home from five yards out. And Tunisia's hopes of getting back into the game were effectively ended when Aymen Abdennour was sent off for elbowing Ayew.

Mali and Ghana are through to the semifinals of the Africa Cup of Nations .
Seydou Keita scores the winning spot-kick as Mali beat Gabon on penalties .
Ghana are taken to extra time by Tunisia before securing a 2-1 success .